Marine Electronics

Sensors, Satellites and Gliders
Track Hurricane Sandy
From vehicles in the water to satellites in the sky, numerous ocean technologies worked overtime tracking Hurricane Sandy as it rolled over the U.S. East Coast in October.

The instruments recorded the precise time the storm-tide arrived, how ocean and inland water levels changed, the depth of the storm-tide and how long it took for the water to recede. This data will be used to assess storm damage, discern between wind and flood damage and improve computer models used to forecast future coastal inundation.

Liquid Robotics Inc.'s (Sunnyvale, California) Wave Glider Mercury survived Hurricane Sandy and successfully piloted through winds up to 70 knots while transmitting weather data in real time. One hundred miles due east of Toms River, New Jersey, the weather sensors on the Wave Glider gathered data from the ocean surface, reporting a plunge in barometric pressure of more than 54.3 millibars to a low of 946 millibars as Sandy neared landfall.

Prior to the hurricane, scientists from Liquid Robotics, Sonardyne International Ltd. (Yateley, England), Rutgers University and the Mid-Atlantic region of the U.S. Integrated Ocean Observing System deployed the Wave Glider and two Sonardyne undersea nodes as part of an ocean-observing technology demonstration project for ocean measurement and tsunami detection.

Oceanographers at Rutgers University were also keeping an eye on Sandy, collecting data from a Slocum glider that had been deployed several days before the storm. Over the next 12 days, the glider transmitted data hourly, according to NewsWorks.org.

NOAA and NASA satellites also observed the storm, with NASA creating 3D images of Hurricane Sandy with data from its Tropical Rainfall Measuring Mission satellite. The Geostationary Operational Environmental Satellites (GOES) captured a global view of Hurricane Sandy, from birth to landfall.

The method for finding undetonated underwater explosives is very similar to that used to detect underground mineral deposits, said CSIRO electrical engineer Keith Leslie.

'Our highly sensitive sensor—the high-temperature superconducting tensor gradiometer—delivers significantly more information about the target's magnetic field than conventional sensors used for this type of detection,' Leslie said. 'It provides data on the location, characterization and magnetic qualities of a target—whether it is a gold deposit or an explosive.'

More than 10 million acres of coastal waters are contaminated by undetonated explosives, according to SERDP. Typically, these small explosives rust and corrode at sea, making them even more dangerous.

The CSIRO sensor can provide geological information that discriminates between prospective and nonprospective areas or targets. It avoids unnecessary drilling and minimizes the risk of overlooking valuable mineral deposits.

The sensor has been proved in a stationary laboratory environment. Trials have been conducted to prove it in motion, in preparation for anticipated underwater trials.

WFS Tests New Modem
At Underwater Centre WFS Technologies (West Lothian, Scotland) tested its Seatooth S100, a new mobile, wireless subsea modem developed for underwater applications from 100 to 4,000 meters, at The Underwater Centre, a subsea testing and training facility in Fort William, Scotland.

The Seatooth S100 was trialed in the Underwater Centre's 1.5-million-liter indoor seawater tank, which allowed the WFS team to observe and monitor their equipment in one location without tidal drift.

The modem can provide a reliable digital wireless communication link or logging device up to a 5-meters range. It is equipped with standard data communication interfaces, making it suited to sensor and underwater vehicle applications. The Seatooth can be deployed on temporary or permanent installations for subsea applications including data logging, upgrading subsea equipment and wireless backup.

MSI Provides Real-Time Current Systems for Seismic Operations
Services International (Pty) Ltd. (MSI), based in Cape Town, South Africa, said in November that it had completed a real-time current measurement program for CGG Veritas (Paris, France) to support seismic operations offshore the Ivory Coast.

The current measurement system was installed on the support vessel Tanux-1, and provided real-time current profile data both on the Tanux-1, as well as via radio to the seismic vessel Vanquish. The data gathered over 110 days were used to model the effects of localized currents on the towed seismic array.

The system comprised a Teledyne RDI (Poway, California) 300-kilohertz acoustic Doppler current profiler (ADCP), cabled to a PC running Teledyne RDI's VmDas software. The software controlled the operation of the ADCP, as well as displayed the data in real time on the Tanux-1.

A Hemisphere GPS (Calgary, Canada) provided positioning and navigation data to the VmDas software so that the vessel motion was removed from the measurements.

Data was then automatically exported to a text file, which was transmitted via Satel (Salo, Finland) radio modem to the Vanquish. There it was captured by a Campbell Scientific (Logan, Utah) data logger and displayed using LoggerNet software.

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